Prevention of evaporation



Nov. 1, 1927.

R. E. WILSON PREVENTION OF EVAPORATION Filed Oct. 8. 1924 pipe line entering a station at which are filled by the incoming pipe line Patented Nov. 1, 1 927.-

UNITED STATES PATENT OFFICE;

ROBERT E. .WILSON, 0F CHIGAGO,.ILLI1\TOIS, ASSIGNOR TO STANDARD OIL COMPANY OF WHITING, INDIANA, A CORPORATION OF INDIANA.

PREVENTION OF EVAPORATIONQ Application filed October a, 1924. Serial No. 742,436.

valved branch lines 6 and 7, which connect it with the tanks A and B. The tanks A and B are provided with the valved discharge lines 8 and 9 respectively, which lead to the intake 10 of the pump or pumps 11, by which the oil is forced into the'next pipe line section 12. In'normal practice one of the tanks (for example, tank A) is filled by the incoming pipe line section 5 while the previously .filled tank B is emptied by the pump 11 and the oil discharged into the outgoing pipe line section 12. The valves of the various lines are then so set that line 6 is open, line 7 closed, line 8 closed and line 9 open. Lines 6 and 9 are then closed and lines 7 and 8 opened with the result that tank A is emptied into the outgoing pipe line section, while tank. B is being filled by the incoming oil.

The storage tanks A andB are provided with substantially tight covers ,13 and 14 respectively, having vents in' their vapor spaces as indicated at 15 and 16 (Fig. 2). The vents 15 and 16 from the vapor spaces of tanks A and B respectively open into the pipes 17 and 18, which connect with the common pipe or manifold 19, which descends to near ground level and connects with the interior of a collapsible bag or container 20, preferably of fabric impervious to petroleum oil vapors, for example, such as described in the prior application of myself and another, Serial No. 648,161, filed June 27 1923. The collapsible 'bag or breather bag 20 may suitably be constructed as shown in my prior application Serial No. 636,596,. filed May 4, 1923, or in my application Ser1alNo. 7 02,029, filed March 26, 1924. At a suitable point beforethe pipe 19 enters the breather bag, itis connected by ashort pipe 'sect1on 21 to a suitable two-way seal 22, or other suit- I able pressure relief device, preferably adjusted to open in either direction under relative slight excess pressure; for example, 0.3 to 0.5 inches water pressure. we

The rates of filling and of discharge of the tanks are preferably made approximately-equal in carrying out this invention and in operating in accordance with this invention, using storage tanks for other pa r-- 1 poses and in other circumstances, it is desirable that the rate of filling and emptying of the respective storage tanks having their, vapor spaces interconnected shall be approximately the same. As the one tank is filled, itsvapor 1:

The present invention relates to improvements in the prevention of evaporation from storage tanks of volatile liquids, more particularly gasoline, crude petroleum oil, and the like. It is directed more particularly to the prevention of evaporation from tanks in which the storage is of a more or less temporary character, such as pipe line storage tanks, run down tanks, and the like. It will be fully understood fromthe following description, illustrated by the accompanying drawings, in which:

Figure 1 is a diagrammatic plan view of a system embodying the invention; and.

Fig. 2 is a diagrammatic elevation showing the tanks of Fig. 1.

It is frequently necessary or advisable, in pipe lines, refineries, and the like, to interrupt the flow of volatile liquids, using for this purpose temporary storage tanks or run down tanks. Thus, in pipe line pumping practice, two or more large temporary storage tanks are placed at predetermined intervals in the line, one of the tanks being with the expulsion of vapor charged air while another is emptying into the outgoing line, the operations being reversed when the one tank is filled and the other emptied. A similar arrangement is employed in the handling of many refinery stocks,'particularly those requiring further distillation or other treatment, such as pressure distillate, etc.

As now practiced, severe evaporation losses are entailed in the use of temporary storage tanks, as above set forth, and it is the object of the present invention to prevent or substantially'reduce such evaporation losses. The invention is described herein in connection with the use of temporary storage tanks in pipe line practice, in which the relatively great volume of the tanks. employed and their frequent filling and emptying causes very great evaporation losses. It will be understood, of course, that the invention may also be employed in refinery practice and in other circumstances in which temporary storage tanks are usedin a similar manner to interrnptthe flow of more or less volatile liquids.

Referring more particularly to the drawings, the numeral 5 indicates an incoming psrovided the temporary storage tanks A and The p pe 11118 5 is provided with the space decreases and vapors are forced out through the vent. At the same time, the emptying ofthe. other tank causes an increase in volume of its vapor space, and the vapor spaces being interconnected, the flowing vapor space in the tank being emptied ordinary circumstances, particularly when I it desirable or necessary,

serves as a reservoir for the vapors being forced out of the tank being filled. Under into the breather bag 20, excesses of pressure in either direct'on being taken care of by the seal 22.

I claim: 7 r 1. The method of preventing evaporation from systems wherein a continuous flow of petroleum oil containing volatile constituents is interrupted by a plurality oftemporary storage tanks,.one of which is filled while another is emptied, which comprises interconnecting the vapor spaces of the tanks 7 being filledand emptied and providing 9.

communication between the interconnected i vapor spaces of said tanks and a collapsible container impervious to petroleum 011 wtpor 2. In a temporary storage apparatus, in-

coming and outgoing flow lines, a plurality" of closed storage tanks, means for connecting said storage tanks witheach of said lines, means whereby one of said tanks may be placed in communication with the incoming line while another is in communication 7 with the outgoing line, whereby one of said tanks is filled while the other is emptied, conduits interconnecting the vapor spaces of said tanks, a collapsible member impervious. to petroleum vapors, and a common pipe connecting said conduits with the collapsible member. v

3. In temporary storage apparatus, incoming and outgoing flow lines, a plurality of closed storage tanks, means for connecting said storage tanks with each of said lines, means whereby certain of said tanks may be placed in'commun'ication with the incoming line, whereby one of said tanks is filled while the other is emptied, conduits interconnecting the vapor spaces of said tanks, a collapsible member impervious to petroleum vapors, a common pipe connecting said conduits with thecollapsible member, and a pressure relief v'alveconnected to said pipe-- ROBERT E. WILSON. 

